Whether in times of war or peace, American anthems have been fan-favorite country songs for decades, and there are a slew of country tunes that proudly proclaim the beauty and benefits of the United States of America.

In the '80s Willie Nelson, Waylon Jennings, Kris Krisofferson, and Johnny Cash - four of the biggest stars in America - joined forces to form a true country music super-group, and revolutionize American music.The "super-group" will be the focus of a new PBS documentary titled …